Campbell’s Biology, 9e (Reece et al.)
Chapter 54 Community Ecology
The organization of this chapter has remained the same as in previous editions, but questions have been
upgraded and revised to reflect the material covered in the 9th edition. More art and scenario question
sets have been included for variety. There is an even balance of question skill level from fundamental
knowledge to those requiring synthesis and evaluation of material learned.
Multiple-Choice Questions
1) Which of the following statements is consistent with the principle of competitive exclusion?
A) Bird species generally do not compete for nesting sites.
B) The random distribution of one competing species will have a positive impact on the population
growth of the other competing species.
C) Two species with the same fundamental niche will exclude other competing species.
D) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted
of two competing species.
E) Natural selection tends to increase competition between related species.
2) According to the competitive exclusion principle, two species cannot continue to occupy the same
A) habitat.
B) niche.
C) territory.
D) range.
E) biome.
3) Which of the following best describes resource partitioning?
A) competitive exclusion that results in the success of the superior species
B) slight variations in niche that allow similar species to coexist
C) two species that can coevolve to share identical niches
D) differential resource utilization that results in a decrease in community species diversity
E) a climax community that is reached when no new niches are available
4) As you study two closely related predatory insect species, the two-spot and the three-spot avenger
beetles, you notice that each species seeks prey at dawn in areas without the other species. However,
where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the
morning. When you bring them into the laboratory and isolate the two different species, you discover
that the offspring of both species are found to be nocturnal. You have discovered an example of
A) mutualism.
B) character displacement.
C) Batesian mimicry.
D) facultative commensalism.
E) resource partitioning.
5) Resource partitioning would be most likely to occur between
A) sympatric populations of a predator and its prey.
B) sympatric populations of species with similar ecological niches.
C) sympatric populations of a flowering plant and its specialized insect pollinator.
D) allopatric populations of the same animal species.
E) allopatric populations of species with similar ecological niches.
6) Which of the following is an example of cryptic coloration?
A) bands on a coral snake
B) brown or gray color of tree bark
C) markings of a viceroy butterfly’s wings
D) colors of an insect-pollinated flower’s petals
E) a “walking stick” insect that resembles a twig
7) Which of the following is an example of Müllerian mimicry?
A) two species of unpalatable butterfly that have the same color pattern
B) a day-flying hawkmoth that looks like a wasp
C) a chameleon that changes its color to look like a dead leaf
D) two species of rattlesnakes that both rattle their tails
E) two species of moths with wing spots that look like owl’s eyes
8) Which of the following is an example of Batesian mimicry?
A) an insect that resembles a twig
B) a butterfly that resembles a leaf
C) a nonvenomous snake that looks like a venomous snake
D) a fawn with fur coloring that camouflages it in the forest environment
E) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish
9) Which of the following is an example of aposematic coloration?
A) stripes of a skunk
B) eye color in humans
C) green color of a plant
D) colors of an insect-pollinated flower
E) a katydid whose wings look like a dead leaf
10) Dwarf mistletoes are flowering plants that grow on certain forest trees. They obtain nutrients and
water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf
mistletoes. Which of the following best describes the interactions between dwarf mistletoes and trees?
A) mutualism
B) parasitism
C) commensalism
D) facilitation
E) competition
11) Evidence shows that some grasses benefit from being grazed. Which of the following terms would
best describe this plant-herbivore interaction?
A) mutualism
B) commensalism
C) parasitism
D) competition
E) predation
12) Which of the following would be most significant in understanding the structure of an ecological
community?
A) determining how many species are present overall
B) determining which particular species are present
C) determining the kinds of interactions that occur among organisms of different species
D) determining the relative abundance of species
E) determining how many species are present overall, which particular species are present, the kinds of
interactions that occur among organisms of different species, and the relative abundance of species
13) Which of the following studies would a community ecologist undertake to learn about competitive
interactions?
A) selectivity of nest sites among cavity-nesting songbirds
B) the grass species preferred by grazing pronghorn antelope and bison
C) nitrate and phosphate uptake by various hardwood forest tree species
D) stomach analysis of brown trout and brook trout in streams where they coexist
E) selectivity of nest sites among cavity-nesting songbirds, the grass species preferred by grazing
pronghorn antelope and bison, nitrate and phosphate uptake by various hardwood forest tree species, and
stomach analysis of brown trout and brook trout in streams where they coexist
14) White-breasted nuthatches and Downy woodpeckers both eat insects that hide in the furrows of bark
in hardwood trees. The Downy woodpecker searches for insects by hunting from the bottom of the tree
trunk to the top, whereas the white-breasted nuthatch searches from the top of the trunk down. These
hunting behaviors best illustrate which of the following ecological concepts?
A) competitive exclusion
B) resource partitioning
C) character displacement
D) keystone species
E) bottom-up and top-down hypotheses
15) Monarch butterflies are protected from birds and other predators because of cardiac glycosides they
incorporate into their tissues from eating milkweed when they were in their caterpillar stage. The wings
of a different species of butterfly, the Viceroy, look nearly identical to the Monarch so predators that
have learned not to eat the bad-tasting Monarch avoid Viceroys as well. This example best describes
A) aposmatic coloration.
B) cryptic coloration.
C) Batesian mimicry.
D) Müllerian mimicry.
E) mutualism.
16) Prairie dogs once covered the expanses of the Great Plains. Their grazing made the grass more
nutritious for the huge herds of bison, and they were preyed upon by a variety of snakes, raptors, and
mammals. In fact, the black-footed ferret (now endangered) specialized in prairie dog predation. Today,
increases in housing and agricultural developments have eradicated many prairie dog towns. Which of
the following statements about prairie dogs is true?
A) Their realized niche has expanded.
B) They have a competitive relationship with bison.
C) They are probably a poor candidate for keystone species.
D) Their fundamental niche has been compromised.
E) Their fundamental niche has expanded.
17) Which statement best describes the evolutionary significance of mutualism?
A) Mutualism offers more biodiversity to a community.
B) Individuals partaking in a mutualistic relationship are more resistant to parasites.
C) Interaction increases the survival and reproductive rates of mutualistic species.
D) Mutualistic interaction lessens competition in communities where it is present.
E) Mutualistic relationships allow organisms to synthesize and use energy more efficiently.
18) How might an ecologist test whether a species is occupying its realized or its fundamental niche?
A) Study the temperature range and humidity requirements of the species.
B) Observe if the niche size changes after the addition of nutritional resources to the habitat.
C) Observe if the niche size changes after the introduction of a similar non-native species.
D) Measure the change in reproductive success when the species is subjected to environmental stress.
E) Remove a competitor species to see if the species expands its range.
19) What percent of all species on Earth are parasites?
A) 1%
B) 5%
C) 25%
D) 33 1/3%
E) 50%
20) Which of the following terms is used by ecologists to describe the community interaction where one
organism makes the environment more suitable for another organism?
A) parasitism
B) mutualism
C) inhibition
D) facilitation
E) commensalism
21) How did Eugene Odum describe an ecological niche?
A) the “address” of an organism
B) an entity that is synonymous with an organism’s specific trophic level
C) an organism’s “profession” in the community
D) the organism’s role in recycling nutrients in its habitat
E) the interactions of the organism with other members of the community
22) Approximately how many kg of carnivore biomass can be supported by a field plot containing 1,000
kg of plant material?
A) 10,000
B) 1,000
C) 100
D) 10
E) 1
23) The energetic hypothesis and dynamic stability hypothesis are ideas that attempt to explain
A) plant defenses against herbivores.
B) the length of food chains.
C) the evolution of mutualism.
D) resource partitioning.
E) competitive exclusion.
24) In a tide pool, 15 species of invertebrates were reduced to eight after one species was removed. The
species removed was likely a(n)
A) pathogen.
B) keystone species.
C) herbivore.
D) resource partitioner.
E) mutualistic organism.
25) Elephants are not the most dominant species in African grasslands, yet they influence community
structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting
activities of the elephants. Take away the elephants, and the grasslands convert to forests or to
shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the
following describes why elephants are the keystone species in this scenario?
A) Essentially all of the other species depend on the presence of the elephants to maintain the
community.
B) Grazing animals depend upon the elephants to convert forests to grassland.
C) Elephants prevent drought in African grasslands.
D) Elephants are the biggest herbivore in this community.
E) Elephants help other populations survive by keeping out many of the large African predators.
26) According to bottom-up and top-down control models of community organization, which of the
following expressions would imply that an increase in the size of a carnivore (C) population would
negatively impact on its prey (P) population, but not vice versa?
A) P ← C
B) P → C
C) C ↔ P
D) P ← C → P
E) C ← P →
27) Which of the following is the most accepted hypothesis as to why invasive species take over
communities into which they have been introduced?
A) Invasive species are more aggressive than native species in competing for the limited resources of the
environment.
B) Invasive species are not held in check by the predators and agents of disease that have always been in
place for the native species.
C) Humans carefully select which species will outcompete nuisance native species.
D) Invasive species have a higher reproductive potential than native species.
E) Invasive species come from geographically isolated regions, so when they are introduced to regions
where there is more competition, they thrive.
28) Biomanipulation can best be described as
A) removing many of the next higher trophic level organisms so that the struggling trophic level below
can recover.
B) a means of reversing the effects of pollution by applying antidote chemicals that have a neutralizing
effect on the community.
C) an example of how one would use the bottom-up model for community restoration.
D) adjusting the numbers of each of the trophic levels back to the numbers that they were before human
disturbance.
E) monitoring and adjusting the nutrient and energy flow through a community with new technologies.
29) Imagine five forest communities, each with 100 individuals distributed among four different tree
species (W, X, Y, and Z). Which forest community would be most diverse?
A) 25W, 25X, 25Y, 25Z
B) 40W, 30X, 20Y, 10Z
C) 50W, 25X, 15Y, 10Z
D) 70W, 10X, 10Y, 10Z
E) 100W, 0X, 0Y, 0Z
30) Why are food chains relatively short?
A) Top-level feeders tend to be more numerous than lower-trophic-level species.
B) Top-level feeders tend to be small but are capable of conserving more energy.
C) Longer chains are less stable and energy transfer between levels is inefficient.
D) There are only so many organisms that are adapted to feed on other types of organisms.
E) Food chain length is ultimately determined by the photosynthetic efficiency of producers.
31) Which term do ecologists use to describe the ability of a community either to resist change or to
recover to its original state after change?
A) stability
B) succession
C) partitioning
D) productivity
E) competitive exclusion
32) According to the nonequilibrium model,
A) communities will remain in a climax state if there are no human disturbances.
B) community structure remains stable in the absence of interspecific competition.
C) communities are assemblages of closely linked species that are irreparably changed by disturbance.
D) interspecific interactions induce changes in community composition over time.
E) communities are constantly changing after being influenced by disturbances.
33) In a particular case of secondary succession, three species of wild grass all invaded a field. By the
second season, a single species dominated the field. A possible factor in this secondary succession was
A) equilibrium.
B) facilitation.
C) immigration.
D) inhibition.
E) parasitism.
34) The 1988 Yellowstone National Park lodgepole pine forest fires were likely the result of
A) overgrazing by elk.
B) infrequent rain episodes.
C) years of fire suppression by humans.
D) unextinguished campfires.
E) geysers.
35) Why do moderate levels of disturbance result in an increase in community diversity?
A) Habitats are opened up for less competitive species.
B) Competitively dominant species infrequently exclude less competitive species after a moderate
disturbance.
C) The environmental conditions become optimal.
D) The resulting uniform habitat supports stability, which in turn supports diversity.
E) Less-competitive species evolve strategies to compete with dominant species.
36) Species richness increases
A) as we increase in altitude in equatorial mountains.
B) as we travel southward from the North Pole.
C) on islands as distance from the mainland increases.
D) as depth increases in aquatic communities.
E) as community size decreases.
37) There are more species in tropical areas than in places more distant from the equator. This is
probably a result of
A) fewer predators.
B) more intense annual solar radiation.
C) more frequent ecological disturbances.
D) fewer agents of disease.
E) fewer predators, more intense annual solar radiation, more frequent ecological disturbances, and
fewer agents of disease.
38) A community’s actual evapotranspiration is a reflection of
A) solar radiation, temperature, and water availability.
B) the number of plants and how much moisture they lose.
C) the depth of the water table.
D) wind speed and the frequency of wind gusts.
E) plant biomass and plant water content.
39) Why do tropical communities tend to have greater species diversity than temperate or polar
communities?
A) They are less likely to be affected by human disturbance.
B) There are fewer parasites to negatively affect the health of tropical communities.
C) Tropical communities are low in altitude, whereas temperate and polar communities are high in
altitude.
D) Tropical communities are generally older than temperate and polar communities.
E) More competitive dominant species have evolved in temperate and polar communities.
40) Which of the following is a correct statement about the McArthur/Wilson Island Equilibrium
Model?
A) The more species that inhabit an island, the lower the extinction rate.
B) As the number of species on an island increases, the emigration rate decreases.
C) Competitive exclusion is less likely on an island that has large numbers of species.
D) Small islands receive few new immigrant species.
E) Islands closer to the mainland have higher extinction rates.
41) Which of the following best describes the consequences of white-band disease in Caribbean coral
reefs?
A) Staghorn coral has been decimated by the pathogen, and Elkhorn coral has taken its place.
B) Key habitat for lobsters, snappers, and other reef fishes has improved.
C) Algal species take the place of the dead coral, and the fish community is dominated by herbivores.
D) Algal species take over and the overall reef diversity increases due to increases in primary
productivity.
E) Other coral species take the place of the affected Staghorn and Elkhorn species.
42) Zoonotic disease
A) is caused by suborganismal pathogens such as viruses, viroids, and prions only.
B) is caused by pathogens that are transferred from other animals to humans by direct contact or by
means of a vector.
C) can only be spread from animals to humans through direct contact.
D) can only be transferred from animals to humans by means of an intermediate host.
E) is too specific to study at the community level, and studies of zoonotic pathogens are relegated to
organismal biology.